This application claims the benefit of Japanese Patent Application Number 2004-355811 filed on Dec. 8, 2004, the entirety of which is incorporated by reference.
1. Field of the Invention
The present invention relates to a cutting tool, such as a circular saw or a cutter, in which a main body having a cutting blade that rotates driven by a motor is provided on a base, and the cutting blade protrudes below the base so as to cut a workpiece.
2. Description of the Related Art
A conventional circular saw has a base which is rectangular in a plain view and a main body provided on the base and having a circular saw blade (cutting blade) driven to rotate by a motor. When the saw blade protrudes below the base, and the base is slid on the workpiece, the workpiece is cut by the saw blade. In this circular saw the front end of a blade case covering the upper part of the saw blade is mounted on the base rotatably in the upper and lower directions. On the other hand, the rear end of the blade case can be slid along an arcuate guide member standing on the base, and can be fixed at an arbitrary position along the guide member by a clamp mechanism provided on the blade case. As a result, an amount of protrusion of the saw blade (cutting depth) from the base can be adjusted.
As a well-known clamp mechanism, the Japanese Patent No. 2829714 discloses a structure including a blade case and a bolt threadedly mounted thereto for penetrating a guide member. Then a thumb nut is screwed to the bolt, so that the guide member is pressed and fixed to the inner surface of the blade case. On the other hand, the Japanese Patent No. 3427431 discloses a structure including a blade case and a cam lever for pressing a guide member provided along the outer circumference of the blade case. With this cam lever, the guide member is pressed and fixed to the outer surface of the blade case.
However, in a structure with a thumb nut screwing as disclosed in the Japanese Patent No. 2829714, rotative operation of the thumb nut in accordance with cutting depth adjustment is troublesome, which deteriorates operability. On the other hand, a cam lever disclosed in the Japanese Patent No. 3427431 improves operability compared with the above structure, because a guide member can be clamped or unclamped by rotative operation of the cam lever. Nevertheless, since powerful force is required to press and fix the guide member, a load on the cam lever in accordance with rotative operation increases, so that improvement of operability is insufficient.
In order to solve the above problem, an object of the present invention is to provide a cutting tool with excellent operability, adopting a lever structure to a clamp mechanism for lightly clamping and unclamping a guide member.